Westminster Shorter Catechism

Q59

Which day of the seven hath God appointed to be the weekly sabbath?

From the beginning of the world to the resurrection of Christ, God appointed the seventh day of the week to be the weekly sabbath143; and the first day of the week ever since, to continue to the end of the world, which is the Christian sabbath144.
Duty
Ch. XXI Of Religious Worship, and the Sabbath Day

Scripture Proofs

143
Genesis 2:2-3Exodus 20:11
144
Mark 2:27-28Acts 20:71 Corinthians 16:2Revelation 1:10